Posted by on December 23, 2004 at 17:54:29:
The United States is facing increasing international pressure to place limitations on the use of military sonar, the underwater equivalent of radar that has been linked to mass strandings of whales. In October, the European Union Parliament called for its member states to develop a moratorium on all types of military sonar. Two weeks ago, the IUCN-World Conservation Union, a group of 70 nations and 400 nongovernmental organizations, overwhelmingly passed a resolution urging governments to limit the use of loud noise sources in the world's oceans, including military sonar, oil and gas exploration and commercial shipping, until the effects on marine life are better understood. The United States abstained from the vote. The measure also said that sonar and other activities should be avoided entirely in areas where vulnerable species live. The Scientific Committee of the International Whaling Commission and the 16 member nations of the Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area also issued warnings in the last few months regarding the use of sonar.
Military active sonar systems emit sound waves that scan hundreds of thousands of square miles of ocean waters the way a spotlight would search on land. The sound signal bounces off objects and sends back information to receivers. Some mid-frequency active sonar systems can put out more than 235 decibels, as loud as a Saturn V rocket at launch. The U.S. Navy is the biggest user of mid-frequency active sonar in the world -- and government officials do not require permits to regulate its use.
According to scientific studies, severe noise can interfere with the survival of the ocean creatures that depend on sound to navigate, find food, locate mates, avoid predators and communicate with one another. In more than a dozen instances dating back to the 1960s, whales have stranded themselves on beaches and died at the time of naval training exercises miles away using mid-frequency active sonar. In 2000 a stranding of 16 beaked and minke whales in the Bahamas brought attention to the issue and scientists later found brain hemorrhaging in the animals, which is consistent with injury from sound.
Last July, four environmental groups, including the International Fund for Animal Welfare and the Natural Resources Defense Council, sent a letter to the U.S. Navy, asking it to change the way it uses mid-frequency sonar on more than half of its 300 ships and submarines. The Navy has not made public what it has done in response. For more information see: http://www.sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/2004/12/13/MNGOEAB3HJ1.DTL or visit: www.seaflow.org.